In radiographic laser printers, an unexposed radiographic film sheet is removed from a stack of film sheets and transported to an exposure station where it is exposed by a laser to a radiographic image. The unexposed film sheets are contained in a light tight magazine or cartridge which is opened when a film sheet is to be removed. Multiple film sheets positioned in a stack can present significant difficulties to mechanisms designed to remove a single sheet of film from the stack. Film sheets tend to stick together due to the bonding forces which exist between adjacent sheets of film.
German Offenlegungsschrift DE 3705851, filed Feb. 24, 1987, published Sep. 1, 1988, entitled "Automatische Filmeinlegevorrichtung fur Blattfilm-Kassetten", discloses a multiple sheet detector which detects the film sheet(s) after it is removed from a film sheet stack. If multiple sheets are detected, the sheets are returned to the film stack and the sheet removal process is repeated. The process is repeated until a single sheet is removed. This technique is disadvantageous because the repeated complete removal of the sheets from the stack can cause undesirable damage to the sheets.
U.S. Pat. No. 5,303,912, issued Apr. 19, 1994, inventors Blank et al., discloses an improved device for detecting double film sheets, in which double sheet detection is effected while the film sheet is still on the film sheet stack. While the top film sheet is bent in a front area and before the film sheet is removed, a double sheet detector is rotated into contact with the bent film sheet(s). The detector includes two levers which are pivotally mounted relative to each other and also with respect to the film sheet removal assembly. A multiple sheet sensor is mounted on the pivotable levers, which results in electrical conductors connected to the sensor to be continually flexed as the detector is rotated. Although this design may have been useful for its intended purpose, difficulties have arisen in installation and adjustment of the pivotally mounted levers and in failure of the repetitively flexed sensor electrical conductors.